The invention relates to a center sill in the form of a longitudinal beam for accommodating the coupling facilities on a railroad car, the said sill comprises two Z-shaped hollow sections each having an upper section strip and a lower section strip joined by a connecting member. The Z-shaped hollow sections are arranged in mirror image and joined together along their upper section strips. Each hollow section part features a connecting member having a pair of the longitudinal sidewalls joining upper and lower strips and hollow chambers formed by transverse struts running between the sidewalls.
U.S. Pat. No. 4,287,834 shows a a center beam or sill in which a recess has been machined out of the part close to the end of the car to accommodate coupling facilities. Adapter and wear plates reinforce the end of the recess away from the end of the car. In practice it has been found expensive and difficult to install these plates.
The object of the present invention is to develop a center sill as set forth above wherein its assembly is made easier, the stiffness and the resistance to failure by bending of the sill are not diminished but increased and, at the same time, with no loss in strength.